It is well known in the art that cutting tools such as industrial saw blades are provided with center bores (openings) having a variety of sizes. In order to sharpen such tools, it is necessary to position them on machines like grinders such that they are Orotatable about their true center axes. This is commonly handled in shops that process (sharpen) such saw blades by providing, with each machine, a rather large quantity of bushings for selective trial in the saw blade to be finished. While this approach is commonly used, it is difficult and time consuming to find the right bushing to center each saw blade brought to the machine.
Some machinists have provided rather complex mechanisms comprising three jaws and a mechanism for moving the jaws radially outwardly and inwardly selectively to fit a blade. These mechanisms, however, are rather complex and are difficult to use for a wide range of bore sizes.
The device of the present invention is primarily concerned with centering saw blades having different bore sizes on a processing machine. The centering device comprises a mounting plate to be placed on a processing machine having a first, a second, and a third bearing. The third bearing is movable away from or toward the first and second bearing to tighten against the saw blade bore centering the blade onto the grinder movable about the center axis of the blade.